由于抗生性物质在土壤中,尤其是在未消毒的土壤中破坏得很快,所以防治能在土壤中营腐生生活的真菌所引起的植物病害,应该采用能在土壤中长期生活的抗生菌。1956年我们了解了在自然情况下棉田内抗生性放线菌菌量的变化。我们在北京西北郊东方农业生产合作社的棉田内选择了一块相连的棉田, Because antimicrobial substances are rapidly destroyed in soils, especially in unsterile soils, controlling plant diseases caused by fungi living in soils should be based on the use of antibiotics that can live long-term in the soil. In 1956 we learned about the changes in the amount of antibiotic actinomycetes in cotton fields under natural conditions. We chose a contiguous cotton field in the cotton fields of the Eastern Agricultural Cooperatives in the northwestern suburbs of Beijing,